灰岩储层孔缝预测方法

Methods for predicting fissures and caves in limestone reservoir,

灰岩储层的岩石物理特征与砂岩不同,灰岩储层的声学特征主要与孔隙度有关,而与孔隙中的流体成分关系不大。利用地震资料可以唯一地研究储层孔缝发育带的分布范围,其方法有两种:一是利用反射波的振幅或由振幅反演得到的合成声波测井信息,直接预测孔缝发育带;二是通过在常规地震剖面上解释小断层间接预测孔缝发育带。本文通过陕甘宁盆地天池地区和百色盆地上法油田的两个实例,详细讨论了上述方法的具体应用情况,结果表明,利用地震资料预测灰岩储层孔缝发育程度的效果是好的。上述方法也适用预测固结的非碎屑岩储层的孔缝发育带。

The petrophysics of limestone reservoir are different from that of sandstone.The acoustic property of limestone reservoir mainly depends on its porosity, but only has little relation to the fluid content in pores.The distributions of fissures and caves in limestone reservoir can be solely predicted using seismic data.There are two methods for predicting fissures and caves.First, fissure-cave belt can be directly predicted using reflection amplitude or synthetic acoustic logging data obtained from amplitude inversion.Second, fissure-cave belt can be indirectly predicted by interpreting minor faults in conventional seismic sections. Two examples of the Tianchi area in Shanganning basin and the Shangfa oil field in the Baise basin are used to detail how these methods are practically applied.It is shown that to predict fissure-cave density in limestone reservoir using seismic data can bring satisfactory result.These methods are also applicable to prediction of fissure-cave belt in consolidated nonclastic-rock reservoir.